There are applications that require subminiature coaxial connectors in which the center conductor, or pin, has an outside diameter of no more than about 0.5 mm (0.02 inch), and where the connector must have a precisely controlled impedance (usually 50 ohms) for minimal loss. One prior art approach is to inject a flowable dielectric of large dielectric constant such as glass, into a body and around a pin contact, with the glass bonding to both of them. The resulting glass bead may have a decidedly curved front face, and some glass can leak beyond portions of the pin which are intended to be surrounded only by air, thereby significantly affecting the impedance at that portion of the connector. In some installations, the rear of the connector projects into a hole of a grounded metal panel, and the pin contact is connected to a circuit such as one on a circuit board lying behind the panel. If a portion of the panel hole is to form part of the outer coaxial conductor through which the pin projects, then losses are likely there because of imprecision in manufacture and installation. If a socket is to be projected around the rear end of the pin, then this also can lead to impedance changes and consequent losses. A miniature radio frequency (usually at least 100 MHz) coaxial connector whose inner and outer contacts were precisely positioned along their lengths, and especially along the rear of the inner or pin contact up to where it engaged a circuit, would be of value.